The study of the effect of planting date on yield and yield components of different oybean (Glycine max L.) genotypes

Selection of cultivars with high genetic potential and favorable climatic adaptation in each region and exact planting date for maximum utilization of effective factors growth are the necessary management for improvement of soybean yield. Therefore, the effect of planting dates of 19 May, 29 May, 8 June and 18 June on yield and yield components of four intermediate soybean cultivars i.e. Williams, Zan, L17 and M7 was carried out in a split plot based on randomized complete blocks design with four replicates. Using analysis of variance showed that planting date cultivar affected on all traits at one percentage level was significant (P<0.01) planting date on 19 May had the most effect on the traits and the cultivars cultivated on 18 June had the least yield. cv. Williams had the highest values for all of traits.cv. L17 had the least seed and pod numbers, protein and oil yield and cv. Zan had the least seed and pod yield and pod shell weight. Interactions of the factors showed that cv. Williams had the most pod and seed numbers per square meter on 19 May. cv. Williams had the most protein yield (107/3 kg /ha), oil yield (40 kg/ha), seed yield (251.5 kg/ha) and pod yield (356.5 kg/ha) on 29 May.